United Nations Security Council, United Nations (UN) organ whose primary responsibility is the maintenance of international peace and security.

The Security Council originally consisted of 11 members—five permanent members (the Republic of China [Taiwan], France, the Soviet Union, the United Kingdom, and the United States) and six nonpermanent members elected by the UN General Assembly for two-year terms. An amendment to the UN Charter in 1965 increased council membership to 15, including the original five permanent members and 10 nonpermanent members. Among the permanent members, the People’s Republic of China replaced the Republic of China in 1971, and the Russian Federation succeeded the Soviet Union in 1991. The nonpermanent members are generally chosen to achieve equitable representation among geographic regions, with five members coming from Africa or Asia, one from eastern Europe, two from Latin America, and two from western Europe or other areas. Five of the 10 nonpermanent members are elected each year by the General Assembly for two-year terms, and five retire each year. The presidency is held by each member in rotation for a period of one month.

Each member has one vote. On all “procedural” matters—the definition of which is sometimes in dispute—decisions by the council are made by an affirmative vote of any nine of its members. Substantive matters, such as the investigation of a dispute or the application of sanctions, also require nine affirmative votes, including those of the five permanent members holding veto power. In practice, however, a permanent member may abstain without impairing the validity of the decision. A vote on whether a matter is procedural or substantive is itself a substantive question. Because the Security Council is required to function continuously, each member is represented at all times at the United Nations headquarters in New York City.

Any state—even if it is not a member of the UN—may bring a dispute to which it is a party to the attention of the Security Council. When there is a complaint, the council first explores the possibility of a peaceful resolution. International peacekeeping forces may be authorized to keep warring parties apart pending further negotiations (seeUnited Nations Peacekeeping Forces). If the council finds that there is a real threat to the peace, a breach of the peace, or an act of aggression (as defined by Article 39 of the UN Charter), it may call upon UN members to apply diplomatic or economic sanctions. If these methods prove inadequate, the UN Charter allows the Security Council to take military action against the offending nation.

During the Cold War, continual disagreement between the United States and the Soviet Union made the Security Council an ineffective institution. Since the late 1980s, however, the council’s power and prestige have grown. Beginning in the late 1980s, there was a surge in the number of peacekeeping operations (including observer missions) authorized by the Security Council; between 1948 and 1978, only 13 missions had been authorized, but between 1987 and 2000 some three dozen operations were approved, including those in the Balkans, Angola, Haiti, Liberia, Sierra Leone, and Somalia.

In addition to several standing and ad hoc committees, the work of the council is facilitated by the Military Staff Committee, Sanctions Committees for each of the states under sanctions, Peacekeeping Forces Committees, and an International Tribunals Committee.

The composition of the Security Council has been a contentious matter, particularly since the end of the Cold War. Critics have argued that the Security Council and its five permanent members reflect the power structure that existed at the end of World War II, when much of the world was under colonial rule. Reform efforts have remained elusive but have centred on efforts to make the work of the Security Council more transparent and on demands by important non-permanent members, such as Brazil, Germany, India, and Japan (the so-called G-4), to obtain permanent membership—or at least have special status within the Security Council. One proposal put forward by the G-4 countries was to increase the membership of the Security Council to 25 seats by adding six new permanent members, including one each for themselves and two for Africa.

Learn More in these related articles:

international armed forces first used in 1948 to observe cease-fires in Kashmir and Palestine. Although not specifically mentioned in the United Nations (UN) Charter, the use of international forces as a buffer between warring parties pending troop withdrawals and negotiations—a practice...

...government of having ties to al-Qaeda and of continuing to possess and develop weapons of mass destruction, contrary to UN mandates. In November Bush’s secretary of state, Colin Powell, engineered a UN Security Council resolution authorizing the return of weapons inspectors to Iraq. Soon thereafter Bush declared that Iraq was in breach of the new resolution for its failure to cooperate fully...

In July 1987 the UN Security Council had unanimously passed Resolution 598, urging Iraq and Iran to accept a cease-fire, withdraw their forces to internationally recognized boundaries, and settle their frontier disputes by negotiations held under UN auspices. Iraq agreed to abide by the terms if Iran reciprocated. Iran, however, demanded amendments condemning Iraq as the aggressor in the war...